A staff report made public Monday identified seven steps the NRC should take "without delay" as it responds to the March 11 earthquake and tsunami that crippled a nuclear plant in Japan.

Most prominently, the report recommended immediate reviews of seismic and flooding risks at the nation's 104 nuclear reactors. Those risks have come under greater scrutiny in the wake of the Japan crisis and last month's East Coast earthquake, which caused the ground to shake much more than a Virginia nuclear plant was designed to withstand.

The report also said plant operators should be required to improve their response to prolonged power blackouts or events that damage more than one reactor at the same time, as happened in Japan.

The five-member commission was scheduled to discuss the report on Wednesday.

The 21-page report skipped over several recommendations made by an NRC task force, which called for sweeping safety changes for the U.S. nuclear industry in a July report triggered by the Japan crisis.

The staff report said top NRC officials support all 12 task force recommendations, but believe that the proposals singled out Monday have "the greatest potential for safety improvements in the near-term."

An industry group praised the report, but said the proposed changes were likely to take two years or more to implement.

"It takes time to make changes to a nuclear power plant, said Tony Pietrangelo, senior vice president and chief nuclear officer for the Nuclear Energy Institute.

Pietrangelo acknowledged that the Japan and Virginia quakes have increased public awareness of earthquake risks, but said it was important to remember that the Virginia quake did not cause significant damage to the North Anna plant located northwest of Richmond.

Preliminary data from the U.S. Geological Survey indicated that ground movement from the Aug. 23 quake exceeded the plant's "design basis" - the first time that has occurred at an operating U.S. nuclear plant.

NRC officials and the plant's operator, Dominion Resources, said the plant's two reactors did not appear to sustain serious damage. The plant has remained offline since the quake.

The Aug. 23 quake, coming so soon after the Japan crisis, "does heighten attention to seismic (risk), no question about it," Pietrangelo said. But he said the lack of serious damage shows "there's a lot of margin built into these plants."

The NRC has said it plans to order all U.S. plants later this year to update their earthquake risk analyses, a complex exercise that could take two years for some plants to complete.

The NRC review, initiated well before the Japan disaster, marks the first complete update to seismic risk in years for the nation's 104 existing reactors, despite research showing greater hazards.

The two North Anna reactors are among 27 in the eastern and central U.S. that may need upgrades, according to a preliminary NRC review.

The staff report noted that the seismic review could be costly, both for the industry and the NRC, which would have to increase its staff and add specialized expertise. Still, the report said the science on seismic hazards has improved significantly since most plants were built at least three decades ago, making a review appropriate.

Pietrangelo said he hoped regulators would not try to force changes too quickly.

"We don't want to do it twice. We want to do it once and get it right," he said.